For germination and establishment, orchids depend on carbon (C) and nutrients supplied by mycorrhizal fungi. As adults, the majority of orchids then appear to become autotrophic. To compare the proportional C and nitrogen (N) gain from fungi in mycoheterotrophic seedlings and in adults, here we examined in the field C and N stable isotope compositions in seedlings and adults of orchids associated with ectomycorrhizal and saprotrophic fungi. Using a new highly sensitive approach, we measured the isotope compositions of seedlings and adults of four orchid species belonging to different functional groups: fully and partially mycoheterotrophic orchids associated with narrow or broad sets of ectomycorrhizal fungi, and two adult putatively autotrophic orchids associated exclusively with saprotrophic fungi. Seedlings of orchids associated with ectomycorrhizal fungi were enriched in (13) C and (15) N similarly to fully mycoheterotrophic adults. Seedlings of saprotroph-associated orchids were also enriched in (13) C and (15) N, but unexpectedly their enrichment was significantly lower, making them hardly distinguishable from their respective adult stages and neighbouring autotrophic plants. We conclude that partial mycoheterotrophy among saprotroph-associated orchids cannot be identified unequivocally based on C and N isotope compositions alone. Thus, partial mycoheterotrophy may be much more widely distributed among orchids than hitherto assumed.

Faculty of Science University of South Bohemia Branišovská 31 370 05 České Budějovice Czech Republic

Imperial College London and Royal Botanic Gardens Kew TW9 3DS UK

Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research University of Bayreuth 95440 Bayreuth Germany

New Phytol. 2014 Apr;202(2):337-340. doi: 10.1111/nph.12769. PubMed

See more in PubMed

Arditti J, Ghani AKA. 2000. Tansley Review No. 110. Numerical and physical properties of orchid seeds and their biological implications. New Phytologist 145: 367-421.

Bernard N. 1909. L'evolution dans la symbiose des orchideés et leur champignons commensaux. Annales des Sciences Naturelles, Paris 9: 1-196.

Bidartondo MI, Bruns TD, Weiss M, Sergio C, Read DJ. 2003. Specialized cheating of the ectomycorrhizal symbiosis by an epiparasitic liverwort. Proceedings of the Royal Society of London Series B-Biological Sciences 270: 835-842.

Bidartondo MI, Burghardt B, Gebauer G, Bruns TD, Read DJ. 2004. Changing partners in the dark: isotopic and molecular evidence of ectomycorrhizal liaisons between forest orchids and trees. Proceedings of the Royal Society of London Series B-Biological Sciences 271: 1799-1806.

Bidartondo MI, Duckett JG. 2010. Conservative ecological and evolutionary patterns in liverwort-fungal symbioses. Proceedings of the Royal Society of London Series B-Biological Sciences 277: 485-492.

Bougoure JJ, Brundrett MC, Grierson PF. 2010. Carbon and nitrogen supply to the underground orchid, Rhizanthella gardneri. New Phytologist 186: 947-956.

Burgeff H. 1932. Saprophytismus und Symbiose. Studien an tropischen Orchideen. Jena, Germany: Gustav Fischer Verlag.

Cameron DD, Johnson I, Read DJ, Leake JR. 2008. Giving and receiving: measuring the carbon cost of mycorrhizas in the green orchid, Goodyera repens. New Phytologist 180: 176-184.

Chalot M, Javelle A, Blaudez D, Lambilliote R, Cooke R, Sentenac H, Wipf D, Botton B. 2002. An update on nutrient transport processes in ectomycorrhizas. Plant and Soil 244: 165-175.

Dearnaley JDW, Martos F, Selosse M-A. 2012. Orchid mycorrhizas: molecular ecology, physiology, evolution and conservation aspects. In: Hock B, ed. Fungal associations, The mycota IX, 2nd edn. Berlin, Germany: Springer Verlag, 207-230.

Gardes M, Bruns TD. 1993. ITS primers with enhanced specifity for basidiomycetes: application to the identification of mycorrhizae and rusts. Molecular Ecology 2: 113-118.

Gebauer G, Dietrich P. 1993. Nitrogen isotope ratios in different compartments of a mixed stand of spruce, larch and beech trees and of understorey vegetation including fungi. Isotopenpraxis 29: 35-44.

Gebauer G, Meyer M. 2003. 15N and 13C natural abundance of autotrophic and myco-heterotrophic orchids provides insight into nitrogen and carbon gain from fungal association. New Phytologist 160: 209-223.

Gebauer G, Rehder H, Wollenweber B. 1988. Nitrate, nitrate reduction and organic nitrogen in plants from different ecological and taxonomic groups of Central Europe. Oecologia 75: 371-385.

Gebauer G, Schulze ED. 1991. Carbon and nitrogen isotope ratios in different compartments of a healthy and a declining Picea abies forest in the Fichtelgebirge, NE Bavaria. Oecologia 87: 198-207.

Gebauer G, Taylor AFS. 1999. 15N natural abundance in fruit bodies of different functional groups of fungi in relation to substrate utilization. New Phytologist 142: 93-101.

Girlanda M, Segreto R, Cafasso D, Liebel HT, Rodda M, Ercole E, Cozzolino S, Gebauer G, Perotto S. 2011. Photosynthetic Mediterranean meadow orchids feature partial mycoheterotrophy and specific mycorrhizal associations. American Journal of Botany 98: 1148-1163.

Gleixner G, Danier HJ, Werner RA, Schmidt HL. 1993. Correlations between the 13C content of primary and secondary plant products in different cell compartments and that in decomposing basidiomycetes. Plant Physiology 102: 1287-1290.

Holm S. 1979. A simple sequentially rejective multiple test procedure. Scandinavian Journal of Statistics 6: 65-70.

Hynson NA, Bruns TD. 2010. Fungal hosts for mycoheterotrophic plants: a nonexclusive, but highly selective club. New Phytologist 185: 598-601.

Hynson NA, Madsen TP, Selosse M-A, Adam IKU, Ogura-Tsujita Y, Roy M, Gebauer G. 2013a. The physiological ecology of mycoheterotrophy. In: Merckx VSFT, ed. Mycoheterotrophy: the biology of plants living on fungi. Berlin, Germany: Springer Verlag, 297-342.

Hynson NA, Weiss M, Preiss K, Gebauer G, Treseder KK. 2013b. Fungal host specificity is not a bottleneck for the germination of Pyroleae species (Ericaceae) in a Bavarian forest. Molecular Ecology 22: 1473-1481.

Kohout P, Těšitelová T, Roy M, Vohník M, Jersáková J. 2013. A diverse fungal community associated with Pseudorchis albida (Orchideceae) roots. Fungal Ecology 6: 50-64.

Kohzu A, Yoshioka T, Ando T, Takahashi M, Koba K, Wada E. 1999. Natural 13C and 15N abundance of field-collected fungi and their ecological implications. New Phytologist 144: 323-330.

Leake JR. 1994. The biology of myco-heterotrophic (saprotrophic) plants. New Phytologist 127: 171-216.

Liebel HT, Bidartondo MI, Preiss K, Segreto R, Stöckel M, Rodda M, Gebauer G. 2010. C and N stable isotope signatures reveal constraints to nutritional modes in orchids from the Mediterranean and Macaronesia. American Journal of Botany 97: 903-912.

Manning JC, van Staden J. 1987. The development and mobilisation of seed reserves in some African orchids. Australian Journal of Botany 35: 343-353.

Martos F, Dulormne M, Pailler T, Bonfante P, Faccio A, Fournel J, Dubois M-P, Selosse M-A. 2009. Independent recruitment of saprotrophic fungi as mycorrhizal partners by tropical achlorophyllous orchids. New Phytologist 184: 668-681.

McKendrick SL, Leake JR, Taylor DL, Read DJ. 2000. Symbiotic germination and development of myco-heterotrophic plants in nature: ontogeny of Corallorhiza trifida and characterization of its mycorrhizal fungi. New Phytologist 145: 523-537.

McKendrick SL, Leake JR, Taylor DL, Read DJ. 2002. Symbiotic germination and development of the myco-heterotrophic orchid Neottia nidus-avis in nature and its requirement for locally distributed Sebacina spp. New Phytologist 154: 233-247.

Merckx VSFT. 2013. Mycoheterotrophy: an introduction. In: Merckx VSFT, ed. Mycoheterotrophy: the biology of plants living on fungi. Berlin, Germany: Springer Verlag, 1-17.

Ogura-Tsujita Y, Gebauer G, Hashimoto T, Umata H, Yukawa T. 2009. Evidence for novel and specialized mycorrhizal parasitism: the orchid Gastrodia confusa gains carbon from saprotrophic Mycena. Proceedings of the Royal Society of London Series B-Biological Sciences 276: 761-767.

Ogura-Tsujita Y, Yukawa T. 2008. Epipactis helleborine shows strong mycorrhizal preference towards ectomycorrhizal fungi with contrasting geographic distributions in Japan. Mycorrhiza 18: 331-338.

Preiss K, Gebauer G. 2008. A methodological approach to improve estimates of nutrient gains by partially myco-heterotrophic plants. Isotopes in Environmental and Health Studies 44: 393-401.

Rasmussen HN. 2002. Recent developments in the study of orchid mycorrhiza. Plant and Soil 244: 149-163.

Rasmussen HN, Whigham D. 1993. Seed ecology of dust seeds in situ: a new technique and its application to terrestrial orchids. American Journal of Botany 80: 1374-1378.

Rasmussen HN, Whigham D. 1998. The underground phase: a special challemge in studies of terrestrial orchid populations. Botanical Journal of the Linnean Society 126: 49-64.

Selosse M-A, Weiß M, Jany J-L, Tillier A. 2002. Communities and populations of sebacinoid basidiomycetes associated with the achlorophyllous orchid Neottia nidus-avis (L.) L.C.M. Rich. and neighbouring tree ectomycorrhizae. Molecular Ecology 11: 1831-1844.

Smith SE, Read DJ. 2008. Mycorrhizal symbiosis, 3rd edn. New York, NY, USA: Academic Press.

Sommer J, Pausch J, Brundrett MC, Dixon KW, Bidartondo MI, Gebauer G. 2012. Limited carbon and mineral nutrient gain from mycorrhizal fungi by adult Australian orchids. American Journal of Botany 99: 1133-1145.

Stöckel M, Meyer C, Gebauer G. 2011. The degree of mycoheterotrophic carbon gain in green, variegated and vegetative albino individuals of Cephalanthera damasonium is related to leaf chlorophyll concentrations. New Phytologist 189: 790-796.

Taylor AFS, Fransson PM, Högberg P, Högberg MN, Plamboeck AH. 2003. Species level patterns in 13C and 15N abundance of ectomycorrhizal and saprotrophic fungal sporocarps. New Phytologist 159: 757-774.

Taylor DL, McCormick MK. 2008. Internal transcribed spacer primers and sequences for improved characterization of basidiomycetous orchid mycorrhizas. New Phytologist 177: 1020-1033.

Tedersoo L, Pellet P, Kõljalg U, Selosse MA. 2007. Parallel evolutionary paths to mycoheterotrophy in understorey Ericaceae and Orchidaceae: ecological evidence for mixotrophy in Pyroleae. Oecologia 151: 206-217.

Těšitelová T, Těšitel J, Jersáková J, Říhová G, Selosse M-A. 2012. Symbiotic germination capability of four Epipactis species (Orchidaceae) is broader than expected from adult ecology. American Journal of Botany 99: 1020-1032.

Trudell SA, Rygiewicz PT, Edmonds RL. 2003. Nitrogen and carbon stable isotope abundances support the myco-heterotrophic nature and host-specificity of certain achlorophyllous plants. New Phytologist 160: 391-401.

Zimmer K, Hynson NA, Gebauer G, Allen EB, Allen MF, Read DJ. 2007. Wide geographical and ecological distribution of nitrogen and carbon gains from fungi in pyroloids and monotropoids (Ericaceae) and in orchids. New Phytologist 175: 166-175.

Zimmer K, Meyer C, Gebauer G. 2008. The ectomycorrhizal specialist orchid Corallorhiza trifida is a partial myco-heterotroph. New Phytologist 178: 395-400.

Mixotrophy in orchids: facts, questions, and perspectives

Stoichiometry of carbon, nitrogen and phosphorus is closely linked to trophic modes in orchids

Germination and seedling establishment in orchids: a complex of requirements